How to deform the outer part of a torus along one axis?
You can use the Proportional Editing mode :


Select only the outer ring of vertices
Activate the PET with O or with the button (blue arrow in the screenshot)
initiate the scale on the desired axis THEN control the radius of the PET with your mouse wheel

You can try different fallof profiles (the &quot;curve&quot; button right to the PET). &quot;Sphere&quot; seems a good choice.